Highlights • The enhancement of absorption of CO 2 by propylene carbonate in the presence of TiO 2 nanoparticles was investigated. • The experimental results show that the gas absorption rate can be enhanced significantly in the presence of TiO 2 nanoparticles. • The CO 2 absorption enhancement factor firstly increases and then decreases with the increases of solids loadings, which proves the existence of optimal solids loading. • The particle size is also a main factor, which affects CO 2 absorption enhancement factor. • A three-dimensional instantaneous numerous-particle di-mechanism model based on the shuttle mechanism as well as a micro-convection mechanism was developed. • The results calculated by the model are close to the experimental results, which showed the model can predict experimental data very well. Abstract The enhancement of absorption of CO 2 by propylene carbonate in the presence of TiO 2 nanoparticles was investigated. The influences of solids loading and particle size of TiO 2 nanoparticles on the absorption rate were studied experimentally. The results show that the gas absorption rate can be enhanced significantly in the presence of TiO 2 nanoparticles. The CO 2 absorption enhancement factor firstly increases and then decreases with the increases of solids loadings, which proves the existence of optimal solids loading. The particle size is also a main factor, which affects CO 2 absorption enhancement factor. As the particle size increases, the optimal solids loading gradually increases. A three-dimensional instantaneous numerous-particle di-mechanism model based on the shuttle mechanism as well as a micro-convection mechanism was developed. The results calculated by the model are close to the experimental results, which showed the model can predict experimental data very well.

Highlights • The nanofluids based on MEA and MDEA solutions were prepared. • The influences of solid loadings and size of nanoparticle on the CO 2 absorption were investigated. • Most of tested nanoparticles could remarkably improve the gas–liquid mass transfer during the CO 2 absorption process. • The enhancement factor increased with the increase of the total volume flow rate of mixed gas or the initial CO 2 volume fraction. Abstract The nanofluids based on MEA and MDEA solutions were prepared using ultrasonic dispersion method without any surfactant addition to study the influence of nanoparticles on the CO 2 absorption by MEA and MDEA in the bubbling reactor. The influences of various factors including solid loading of nanoparticles, nanoparticle size, nanoparticle type, total volume flow rate of mixed gas and initial CO 2 volume fraction on the CO 2 absorption were investigated. Although the reaction rates of MEA-CO 2 and MDEA-CO 2 were different, the findings about the influence of nanoparticles based on MDEA solution were similar to that based on MEA solution. Most of tested nanoparticles could remarkably improve the gas–liquid mass transfer during the CO 2 absorption process. The CO 2 absorption enhancement factor increased with the increase of the solid loading of nanoparticles up to a maximum value and then decreased. The CO 2 absorption enhancement factor based on the MEA solution for larger nanoparticles was greater than that for smaller nanoparticles. On the other hand, the absorption enhancement effect of nanoparticles based on the MDEA solution depends highly on the type of nanoparticle. It is also found that the enhancement factor based on the MDEA solution increased with the increase of the total volume flow rate of mixed gas or the initial CO 2 volume fraction.